1. Field of the Invention
The invention relates generally to handling, routing and shipping containers. More specifically, the invention relates to systems and methods for automatically placing lids on, and removing lids from, shipping containers.
2. Description of the Related Art
It has been a common practice in the shipping and package delivery industry to ship items in trays such as flat trays and SPBS trays (tubs). Items such as letters and packages are placed in trays, a lid is put on them, and a strap is bound around the tray and lid assembly. One reason for this practice is to protect items from damage and loss during shipping. Also, storing and stacking uniform assemblies is more efficient in terms of time and space, than storing disparate items.
However, putting lids on trays and strapping the assembly at an intermediate location, only to have the strap cut and lids taken off so items can be further routed, is a time consuming and repetitive task. Typically, this task is done manually. A worker receives the assembly, manually cuts the strap, removes the lid, unfolds the lid, sorts and stacks the lid according to, size, and feeds the un-lidded tray to the next station. Then, after the items have undergone the required processing at the intermediate location, a worker reverses this time consuming process. The worker selects the appropriate size lid for the tray, folds it, places it on the tray, puts a strap on the assembly and feeds it to the next station. This manual process is both time-consuming and expensive. Further, the manual process subjects workers to the hazards associated with physically handling a cutter and large numbers of trays. An automated process to place lids on trays and to remove lids from trays would provide an advantage over a manual system.
One problem associated with putting lids on trays has been that items tended to get damaged when the lids are placed on the tray. The unfolded lids usually have four flaps, each corresponding to a tray side, in the finished assembly, two opposing outside flaps remain outside of the tray and the other two opposing inside flaps reside inside the tray between the items and tray sides. However, problems arise because the inside flaps can jam against items, such as letters, that are close to the edges of the tray. In the past, careful attention was needed to ensure that items were not damaged when lids were put on trays.
Accordingly, there is a need for an automated system and method for putting lids on trays and for removing lids from trays. A need also exists for a system that can perform these functions without damaging items in the trays, and to be fed into a device that will put a strap around the assembly. It would be desirable to provide a method that obtains the advantages of the present system while minimizing the need for expensive automated equipment.
In certain embodiments of the present invention there is provided a method and systems that can automatically put lids on and remove lids from different tray sizes or from a single try size. In one embodiment of the invention, a lidding device with a lid manipulator having lid holders holds a lid. Lids are held by a lid holder and at least one end mechanism attached at the end of the lid manipulator, where the end mechanism folds the lid flaps of an appropriate sized lid. Guided by the lid manipulator, lids are positioned on the tray. Trays are passed through the lidding device by automatic means such as a conveyor belt or mechanized rollers. A first advantage of the present invention is the automated handling of trays and lids.
According to another embodiment of the invention, a sensor on the lidding device sizes a tray/lid combination. When removing lids from trays, information from the sensor about the tray/lid dimension allows the lid holders to adapt to different sizes. When attaching lids, the sensor allows the lidding device to match the appropriate sized lid to a given tray. Appropriate unfolded lids are selected from a storage container. The unfolded lid flaps are folded and the lid is guided onto a tray. Thus one advantage of the invention is that a single lidding device can handle trays and lids of differing dimensions. It is not necessary to provide a single machine that is adapted to a single tray/lid size.
A further advantage of the invention is that straps which attach lids to trays may be automatically cut. The trays pass by a cutter that is part of the lidding device. The cutter shears the straps thus releasing the lids from the trays.
Another advantage of the present invention is the high rate at which trays may pass through the lidding device. The automated process of removing lids and attaching lids to trays assures that an acceptably high rate.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claim. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. Thus, the present invention comprises a combination of features, steps, and advantages which enable it to overcome various deficiencies of the prior art. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention, and by referring to the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.